Paralysis of analysis
This Clinician’s Guide summarizes the onslaught of high-sensitivity troponin (hs-Tn) studies and offers these best practices when considering MI rule-out strategies using hs-Tn.
- There are differences in assays. The hs-TnI performs better in early presenters; hs-TnT assay performs better in late presenters. The assay currently approved in the US is hs-TnT.
- Strategies combining clinical scoring systems, such as HEART, etc. plus biomarkers have greater diagnostic accuracy.
- You must know the time of onset of symptoms.
- The author favors strategies with serial hs-Tn testing. This is especially important with early presenters (<2 hours) and with use of the hs-TnT assay (available in the US).
- But there are reasonable single-troponin strategies.
– If onset > 6 hours, then hs-TnI < 99th percentile upper reference limit (URL) is sufficient per European Society of Cardiology (ESC) guidelines.
– If onset > 2 hours, a single hs-Tn I < 5ng/L is acceptable, but dropping the threshold to the assay’s lower limit of detection improves the NPV to 100%.
- The allowable delta troponin depends on time from initial troponin. For hs-TnI, it is a delta of <2 ng/mL at 1-hour or < 3 ng/mL at 3-hours. Or the ESC recommends the 3-hour delta hs-Tn be <99th percentile URL or < 50% of the URL.
Consider these best practices when implementing a high sensitivity troponin strategy to rule out MI. Read SGEM’s Oh Baby You’re Too Sensitive about hs-Tn.
Clinician’s Guide to Early Rule-Out Strategies With High-Sensitivity Cardiac Troponin. Circulation. 2017 Apr 25;135(17):1612-1616. doi: 10.1161/CIRCULATIONAHA.117.026717.
Co-written by Thomas Davis and Clay Smith.